Did you know?

Learn more about the watershed, historical spots, and how you can help protect this valuable resource !

About the Watershed

The Cabin John Creek Watershed is 25 square miles of heavily urbanized land (90% residential/commercial) with its centerpiece being the county's 520 acre Cabin John Stream Valley Park containing the Cabin John Creek and the Cabin John Trail (map). The park, the largest stand of forest and trees in the watershed, was acquired in 1934.

The headwaters of Cabin John Creek originate in the City of Rockville then flows south about 10 miles, passing under Interstate 270, through Cabin John Regional Park, under the Capital Beltway (I-495), the historic Cabin John Bridge, and finally to its confluence with the Potomac River at the C&O Canal near the towns of Cabin John and Glen Echo.

Chances are Cabin John Creek or one of its tributaries are not far from where you live, so take a trash bag on your walks and clean up as you go!

Bogley Branch, Booze Creek, Buck Branch, Congressional Branch, Ken Branch, Old Farm Branch, Snakeden Branch, Thomas Branch

About FoCJC

Friends of Cabin John Creek, Inc. (FoCJC) is a non-profit volunteer citizen group dedicated to the restoration, preservation, and stewardship of the Cabin John Creek watershed. FoCJC was started informally in 1999 in Cabin John, Maryland. FoCJC has grown to include members from within and without the watershed, including residents of Glen Echo, Bethesda, Potomac, and Rockville.

FoCJC regularly collaborates with local organizations including the Montgomery County Department of Environmental Protection, Chesapeake Bay Trust, City of Rockville, Maryland National Capital Park and Planning Commission, The Potomac Conservancy, Audubon Naturalist Society, Alice Ferguson Foundation, and Izaak Walton League of America. Our volunteers organize events and programs, such as Creek Clean-ups, environmental film viewings, stormwater management campaigns, and other activities to educate and motivate local residents to become stewards of Cabin John Creek.

Scotland Community

The Scotland Community, an historic African American enclave, is on the other side of the creek along Seven Locks Road. Beginning in the late 1870s and through the 1880s, former slaves began to take ownership of what would become the Scotland property. At that time, Scotland's approximately 50 families provided a pool of inexpensive labor for nearby farmers. In the mid-1960s, community efforts led to a 100 townhouse development, community center, and the institution of community self-governance which continues to this date. Two principal early families were the Masons and Doves, with descendants still living in the community. [Wikipedia]

Electric Trolley Power Station

As you enter the trail headed south, you see a vestige of the trolley days in Montgomery County. The stone building was built in 1912, using a water wheel to boost electricity to the Washington and Great Falls streetcars running from Chevy Chase to the Great Falls Tavern. It was built in the style of a period farmhouse to blend in with its surroundings. When the trolley was discontinued in 1920, the architect, James Richards, converted it into a private residence and is still a residence today.

So… where are the trolley tracks? They now lay beneath Bradley Blvd.

Magruder's Blacksmith Shop

At the corner of River Road and Seven Locks Road you see a privately owned stone cottage, one of the oldest standing structures in Montgomery County. Originally built by Ninian Magruder before 1751 as the Magruder’s Blacksmith Shop, it played a key role in colonial trade as barrels of tobacco were rolled and goods carried along River Road to Georgetown. The smithy served travelers, farmers, and merchants with shoeing horses, repairing wagons, and creation of ironworks critical to farming and life of the period.

Gibson Grove Church

Look across Seven Locks Road and you will see the wood facade of the Gibson Grove A.M.E Zion Church, associated with the African American settlement of Gibson Grove founded in the 1880s by former slaves. The church was damaged by fire in 2004 and by a fallen tree in July 2015, and there are plans to reconstruct it. Built in 1923 to replace the original log church, the church is an excellent example of 20th century vernacular ecclesiastical architecture.

Mrs. Gibson, an ex-slave from Virginia, purchased the property and in 1898 gave a portion of her property to build the first Gibson Grove A.M.E Zion Church. The first members of the church were baptized in Cabin John Creek.

Native Plants

Cabin John Creek Stream Valley Park has been designated by Montgomery County parks as both a “Biodiversity Area'' and “Best Natural Area” for its combination of native flora and scenery. Perhaps the best time to look for wildflowers is early spring when numerous types of “spring ephemerals'' flower in the sunlight before the trees leaf out. Some common species to look for then include Dutchman’s Breeches (Dicentra cucullaria), Virginia Bluebells (Mertensia virginica) and Wild Phlox (Phlox divaricata) among many others. In later summer, look for Jack in the Pulpit (Arisaema triphyllum), which is common throughout the park, as deer seem to avoid it.

Also, check out this more complete plant list for Cabin John Creek Stream Valley Park. Use the iNaturalist app to identify plants along the trail.

Create a conservation garden of native plants in your yard to support the ecosystem!

Trees

While much, if not all, of the forests of Cabin John Creek Stream Valley Park have been cut over several times in the last few centuries, they have now been given nearly a century of protection and you can find some impressive specimens in the park. Some of the most common species to look for include American Beech (Fagus grandifolia), easily recognized by its very smooth park (unfortunately frequently marred by graffiti), Tulip Poplar (Liriodendron tulipifera), among the tallest trees in the park, and various species of oaks and maples. In some sections near the creek, look for the Mountain Laurel (Kalmia latifolia), which in late May to early June is profuse with beautiful white flowers.

Mature trees can soak up to 50-100 gallons of water a day and are critical to reducing stormwater runoff, cleaning the water, and preventing erosion.

Plant a shade tree in your yard and help the creek!

Use the iNaturalist app to identify trees by their leaves.

Wildlife

Cabin John Creek Stream Valley Park is home to a good variety of terrestrial wildlife, including mammals, reptiles and amphibians, as well as numerous species of insects. Perhaps the most commonly seen mammal is the gray squirrel, followed closely these days by white-tailed deer. Luckier visitors (particularly in early mornings or later in the afternoon/evening) may see a red fox, raccoon, or even a coyote! Flying squirrels are common, but rarely seen as they are most nocturnal. Common reptiles and amphibians include box turtle, garter snake, american toad, gray tree frog, and red-backed salamander. In summer, look for insects including damselflies, dragonflies, and various species of butterflies and moths, and many more!

Check out this list for species in the watershed and use the iNaturalist app to identify your animal pics.

What's in the Water?

Although relatively poor stream health of Cabin John Creek means that diversity is lower than it should be, the creek nonetheless provides a home for a variety of aquatic species. Fish include Blacknose Dace, Brown Bullhead and Green Sunfish. You may also find crayfish - native Acuminate Crayfish are indicators of better water quality.

See these sites for more information:

Use the iNaturalist app to identify any stream critters or amphibians.

Hidden Creek Critters

There are tiny critters on the bottom of the creek! Larvae for various flies and beetles are critical for the biodiversity and survival of our watershed. They include larvae for dragonflies, damselflies, mayflies, and stoneflies, as well as aquatic worms, leeches and beetles that provide food for our fish, frogs and birds. They are sensitive to pollution and therefore good indicators of water quality. Unfortunately, we tend to find only the hardy critters and so the creek is rated Fair.

FoCJC has a water quality monitoring team that checks 4 times/year for their existence and for chemicals in the creek. We partner with Audubon Naturalist Society and Izaak Walton League of America to report these findings up the chain to support the health of the Chesapeake Bay. To lend a hand with our monitoring program contact us at monitoring@cabinjohncreek.org.

In the winter, we partner with the Izaak Walton League of America on their SaltWatch program, so help us out as citizen scientists, go to SaltWatch and get your free kits! This data is critical to maintaining creek health. You can help by reducing the amount of salt you use in your driveways/sidewalks to melt ice.

Did you know there is a new pesticides law for private lawn care? We all need to do our part to protect our streams and rivers.

So many Birds!

The Cabin John Creek provides critical habitat for numerous species of birds, both resident and migratory. May is a particularly good time of the year to look for birds here, as migration reaches its peak in the early to middle part of the month. Many species return to breed in the area, including the wood thrush and scarlet tanager, alongside the full time residents such as northern cardinal, Carolina wren, Blue jay, Carolina chickadee and many species of woodpeckers. In the late afternoon or early evening, you may hear the “Who Cooks for You?” call of the Barred owl. Around Locust Grove Nature Center, look for Bluebirds using some of the boxes set up and monitored by park volunteers.

While the habitat provided by Cabin John Creek Stream Valley Park is extremely important, the proximity of so many homes does present some threats to our birdlife. You can help by making sure your homes are “bird friendly” including by making your windows more “visible” to birds and keeping cats indoors. Check out the Montgomery Bird Club for more information on birds of the area.

Use the iNaturalist app to identify your pics of birds and the Merlin app to identify them by sound!

Who's Cutting Down that Tree?

Take a look in the creek and you will see the busy work of the beaver that is making this forested wetland his home. As herbivores, they eat leaves, bark, twigs, and roots… but not wood! If left alone, they will eventually build a lodge with the logs and branches they cut down and raise a family of 1-6 kits per year forming a colony of beaver.

They are a keystone species able to modify their environment to provide new wetland habitat for many other species which also improves the water quality. Check out the county’s site on Living with Beavers for more info.

Beaver can reach 60 lbs and have sharp incisors so stay clear and keep your dog close if you see one! They will slap their tail on the water to warn you.

Snap a pic if you see one and use the iNaturalist app to record any sightings.

Kingfisher

What’s all that chattering* about? It is most likely the Belted Kingfisher with its beautiful crest diving and darting along the creek. Known to have existed 2 million years ago, it is a native to Maryland, not an import from India! One of the few native birds where the female is more brightly colored than the male.

These birds, like many, depend on the frogs, aquatic insects and fish in our creeks to survive and make their homes by burrowing 3ft - 8ft into our creek and river banks to raise about 6 chicks a year. Like owls, they regurgitate pellets of undigested bones. This is one species that actually benefits from the deeply eroded creek banks for its nesting, and builds its burrows slanted upward to escape rising flood waters.

Use the iNaturalist app to identify your pics of birds and the Merlin app to identify them by sound!

*Pamela C. Rasmussen/Avian Vocalizations Center

Invasives

We have many invasive plants in the watershed including english ivy, garlic mustard, multiflora rose, japanese honeysuckle, …

An invasive is a plant, insect or animal from another part of the world (introduced intentionally or accidentally), which is capable of spreading rapidly, causing ecological/economic harm or is a threat to human health.

What’s the big deal, aren’t all plants the same?

Many native species have adapted over thousands of years to live in harmony in the ecosystem… animals eat certain plants and some butterflies only lay eggs on specific native plants/trees. This native biodiversity is threatened when a few nasty plant species (invasives) take over and dominate the herbaceous, shrub, or canopy layers of a forest.

Don’t plant invasive species in your yard and replace any existing invasive plants with native species. Check out the county’s site for creating a conservation landscape of native plants. Also, check out this more complete native plant list for Cabin John Creek Stream Valley Park.

Become a Weed Warrior! These volunteers work during the year to control invasives in our county parks.

Use the iNaturalist app to identify the good and bad plants along the trail.

Stormwater

The 25 square miles of the Cabin John Creek Watershed is 90% urbanized which means lots of roofs, pavement and golf courses where trees used to be. Most of the rain water carrying pollutants ends up in our creeks and the Potomac River.

Climate change has caused an increase of 5 inches of average precipitation over the last 90 years in Montgomery County, Maryland. A record was set in 2018 with 64.3" of precipitation.

To keep up with rising annual rainfalls, homeowners can help by soaking it up and slowing it down. The Montgomery County Rainscapes Program offers rebates to residents who install landscaping projects that reduce stormwater impacts. Visit our Stormwater Solutions webpage and the Rainscapes website for details about how to do the projects and qualify for a rebate.

Check out the county’s guidance on planting native trees in your yard to improve the ecosystem, provide shade, and absorb stormwater.

Did you know there is a new pesticides law for private lawn care? We all need to do our part to protect our streams and rivers.

Scoop the Poop! Dog waste is a significant source of bacteria in our creeks.

Mighty Sycamore

This is an excellent specimen of the Sycamore tree with its massive, heavy spreading branches. They typically reach up to 100 to 130 ft high and 5 to 6.5 ft in diameter when grown in deep soils. With its large leaves, it provides plenty of shade. An easy way to identify one is by its thin, mottled bark of brown, green, tan and white that sloughs off the trunk. Did you know that Orioles particularly like to nest in Sycamores?

How old am I?

Good at math? Oh jeez! Given that Sycamore trees average a growth rate in girth of about 1 inch/year… and

"age = circumference / 1in/yr"

then just guess its belt size and take a guess!

Mature trees can soak up to 50-100 gallons of water a day and are critical to reducing stormwater runoff, cleaning the water, and preventing erosion. Plant a shade tree in your yard and help the creek!

Use the iNaturalist app to identify trees by their leaves.